Indicator.



T. B. HEADY.

INDICATOR.

APPLICATION min AUG. n. |915.

.huw 20, 19145` INVENTOR WITNESSES zigiergssa.

UNITED STATES THQMASiB. HEADY, OFPITTSBURGH, PENNSYLVANA.

I YIrrolca'ijna i To allwho'm ztmay 'concer'm" Y Be itknownthat I, 'Tiioiirals B. Honor, residingat' Pittsbiirgh,in lthe county of A lleglien fand-State vof Pennsylvania, a

. citizen 'o the United States, have invented.

or discovered certain new and useful Im'- provements inIndicators, of v vhich improvements the following is avvspeciication.

It is ivell known that the critical ten'iperature or point ofi recaleseence to which steel should be heated for hardening, annealing, etc., varies with the carbonleontent of the steel. Although the critical .temperatures for different grades of steel, e., having different pe'rcenta-ges of carbon are known or can be easily determined, vso that a pyroineter inightbe-cmployed :to ascertain when an article being `heated has reached the proper temperature, suclrmethod has been found cumbersome and unsatisfactory.

The invention described herein has for its object a construction ofindicator, which will becomeoperative aydindicate to the heater that the article being-heated has .at-

" tained the critical temperature, Vregardless 'of whether that;temperature high o r low foi` that' particular article.

- The invention is hereinaftermorel fully described and claimed. Y

In the aci-.ninin inyingdrawing formingr apartjofthis specification, Figure 1 is a sectional-elevation of an indicator embodying.

i'ny'invention, Fig. 2', is anfcnd elevation of the same, and Fig 3' is a sectional elevation of' a second lembodiment of the invention.

In the practice of iny invention, a hollow spool 1 haring insulatcdwire wound thereon to form the coil of an electro-magnet, is arranged in a' Shell l formed of nonuiiagurtic material as aluininu'n. lt. is preferred to interposeisl)esl'os or othernon-confhu-tmof heat between the oil`and thcishcll, as -indicated at 3 to protecthe coil from injury.

-A Core 4Y of Soft iron or .-uiild sier-l is passed through the spool 1 said -corc being nl' :such

Specification of. Letters `Patent Patented-dune 20,1916.

*Application led August 11, v1915.-V Serial N0. 45,077.

shaped Seat the'end ofthecore. To form a bearing forvthe end ofv the core Withinthe shell, it -is` *preferredv to 4reduce a lportion o'f the end of thecore to -form ajournal 6, which -60 has a bearing in-a disk or diaphragm? suitably securedin the- Shell.- The shell is carried by a hollowv stein S' havinga head or en-- largement closing thel open endr-of the shell.

- The wires. or conductors from' the coil. pass G5 through the hollow stem and are connected to a switch 9 preferably embodied in the handle 10, said switch beingalso connected 'l to the wires 11 extending Afrom a suitable generator. The end-oflthecore extending 70 beyond the'casing is provided with oppositely arranged arms v12 which curve down- 4.vardly sov that the greater portion-of the weight of said -arins will be below Vthe axis ofV the coil, thereby insuring .the return of them-ins andeore (go-normal' or horizontal A position, when vree to m'oye as. hereinafter described. Ihe shell orfcasingisprovided with a leg lada'ptedtosupportthe shelll i orv case, said leg. beingpreferablyhf s'uch :i180 'length thatethe distancefrom; thevaixis of the core to the end of tlxe" leg,"vi'i ll be l,ess than j the distance bctweenfthefeore'axis and the A ends" of the `arins ,=so' thatthe'r'i'ds 'of the ai'ins iii'ay be brought hyfafrotation ofthe 85 core into contact with the s urace'on'v which c the legmay. bear. The rotation. of. the l.core is preferably' effected .by-amd 13 extending through the'holloivfstem. 'Suitable meansare`pl-orided intermediate'the inner-end of 90' the rod and core, whercbyfthe former can be caused to engage and rotate the core and then be shifted from such engagement, leavintoY the core entirely free to return automatically to normal or'horizontal position.' 'A 95 desirable construction to thatend'f consists in forming' a fork ll. on the end of the roil. 3 and passing :i pin' l5A through' the core so' as to h1,- engrageil hv the forli when rotated.' ln order lo ins-nro the disengagement'of the mo fork and piu. :i spring is employed for returning the forlt and rod to normal position.

I'l`lnopi-ration ofany in'iproi'od indicator is lcpi-inli-i'it upon lln; \\.rll known fact, that when steel is heated lo the critical tempera.

ture or rw-alcscciico, it becomes non-inagn iic. ln Vusing the indicator, it is pushed into the furnace, the switch 9 being,r closed so that tlucoil and core may be energized.

"l`hc leg 1G rcstingon the article. or on the H0 fnl-namhottmn adjacent tlufreto, the operating rod 13 is rotated to turn thecore and bring one or the other of the arms 112 in contact with the article being heated, and as soon as such contact has been effected, the operating rod is'released so as to be turned by the spring from engagementl with the .core. Ifl the article has reached the state of recalescence, the arms 12 will automatically return to normal orhorizontal position, as soon as released from engagement with the operating rod, but if the article is still mag-l nctic, thearms lwill remain inthe position` to 'gized when the indicator maybe withdrawn without subjecting the instrument to strains when the article is still magnetic, the switch may be omitted and the coil continuously energized and also that the core itself may be permanently magnetized, the coil being omitted, as shown in Fig. 3. In this form, 4the electric coil is omltted and the core 4:* is

permanently magnetized.. This` instrument is used in the same manner as the construe tion shown in Fig. 1, but as it cannot be deenergized, Some vforce is required to detach it from the article being treated, if at the same ti meof making the test," the article haa` not been treated-to the pointvof recalescence.

Hence the form of indicator' having the v.elec- A tromagnet controlledbya switch'.v is preferable for use in testing Asmallzarticles-i ovfarticles of a wei ht within the limit ofthe liftf ing power o the magnet, sothat when making. a test before vrecalescence has been atftained, the article Will not be withdraw when removing the instrument.

By constructing the core with oppositely arranged arms, the ends of which extend below the axis of rotation, one arm will operate as a counterbalance to shift the arm which has been in contact with the article, to normal position. Tbisreturn or indicating movement of the core can be effected in many ways-which will readily suggcst themselves to one skilled in the art, and hence the invention as regards the production of an indicatingA movement is not limited to the specific construction herein shownY and described.

It will be understood that'as regards the broader claims, the term magnet 1s used generically as including both permanent and electro'magnets. Y

I claim herein as my invention:

l.' An instrument for indicating the point of recalescenee of lsteel having in combination a support, a magnet pivotally mounted on said support and provided with an arm -at an angle to the axis of movement of the magnet, means for shifting the magnet to bring said arm intol Contact with the heated article and automatic means for returning the magnet to normal position.

2. An instrument for indicating the point of rccalesctnce of steel, having in combina-l tion a support, am'agnet pivotally mounted on said'fsupport and provided with oppositely extended arms, means for shifting the magnet to bring one of said arms into con-4 tact with the heated article, and automatic means for returning themagnetto normal position. i'

3. An instrument for indicating the point* l' of recalescence of steel having in combination a hollow coll of wire, a core provided at one end witl'roppositely extending arms and rotatablv arranged in said coils, detachable means for rotating the core, ,and automatic means for returning the core toinormal position.

4. An instru'n'ien't for indicating the point of rccalresccnce of steelt having in combina tion an electroanagnet provided with a ro-y tatable core, oppositely dispcsedarms on one end of thc core, the ends of the arms extend- Y ing to one side of the/axis of rotation .of'tne core, means for rotating-the core, andadapted to be returned to normalnposition independentof the core.

sov

the coriand automatic means for returning said rod indepi'ewlent of thc `:ore to normal position. Y

C. .\n instrumrx-it for indicating the point of remilescence of stoel having in combinw' tion a shell or casing formed of nonn'riag rwtif: material and provide-d with a supporting' foot, a magnet rotatably mounted on the shell or casing. and provided at one` rnd with an arm outside of the casing, means for turning the magnet to bring said arm into contact with the article to be heated, and means for automatically returning the magnet to normal position.

In testimony whereof, l my hand.

have hereunto eet 'moms u. umm. 'itncsses A Lice A. TnILL,

` Trios. B. Jorce. 

